681 research outputs found

    Subadult Growth Stunting at Schroeder Mounds (11He177): A Late Woodland Sample from Illinois

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    Constitutional growth delay in subadults may be caused by chronic illness, malnutrition, and/or undernutrition. Very little is known about the community health of the presumptive forager-farmers of the Late Woodland (~ AD 900-1150) period site of Schroeder Mounds (Henderson County, Illinois). In an effort to increase understanding of community health, the subadults (N=15) were examined by age-at-death for evidence of growth stunting as reflected in forelimb shortening. Crural and brachial indices were calculated for those subadults preserving measurable femora and tibiae and/or measurable humeri and radii. These indices were compared by age category to indices calculated from normal bone lengths taken from published clinical data. Stunting was evident for all ages-at-death in the Schroeder Mounds sample. The stunting was contextualized by assessing the presence/absence of potentially causative or synergistically related skeletally visible chronic health stress indicators (i.e., porotic hyperostosis, cribra orbitalia, linear enamel hypoplasia, periostosis). The results indicated that all subadults exhibited growth stunting regardless of the presence of the quantified health issues. This may suggest that stunting is potentially a free-standing osteological marker of developmental stress. Within Schroeder Mounds, stunting may ultimately be due to various environmental (e.g., harvest or resource shortfall) and cultural (e.g., weaning, child labor) factors

    Perturbative Quantum Field Theory at Positive Temperatures: An Axiomatic Approach

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    It is shown that the perturbative expansions of the correlation functions of a relativistic quantum field theory at finite temperature are uniquely determined by the equations of motion and standard axiomatic requirements, including the KMS condition. An explicit expression as a sum over generalized Feynman graphs is derived. The canonical formalism is not used, and the derivation proceeds from the beginning in the thermodynamic limit. No doubling of fields is invoked. An unsolved problem concerning existence of these perturbative expressions is pointed out.Comment: 17pages Late

    Thermal bremsstrahlung probing the thermodynamical state of multifragmenting systems

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    Inclusive and exclusive hard-photon (Eγ>_\gamma > 30 MeV) production in five different heavy-ion reactions (36^{36}Ar+197^{197}Au, 107^{107}Ag, 58^{58}Ni, 12^{12}C at 60{\it A} MeV and 129^{129}Xe+120^{120}Sn at 50{\it A} MeV) has been studied coupling the TAPS photon spectrometer with several charged-particle multidetectors covering more than 80% of 4π\pi. The measured spectra, slope parameters and source velocities as well as their target-dependence, confirm the existence of thermal bremsstrahlung emission from secondary nucleon-nucleon collisions that accounts for roughly 20% of the total hard-photon yield. The thermal slopes are a direct measure of the temperature of the excited nuclear systems produced during the reaction.Comment: 4 pages, 3 figures, Proceedings CRIS 2000, 3rd Catania Relativistic Ion Studies, "Phase Transitions in Strong Interactions: Status and Perspectives", Acicastello, Italy, May 22-26, 2000 (to be published in Nuc. Phys. A

    Patients with IgA nephropathy exhibit high systemic PDGF-DD levels

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    Background. Platelet-derived growth factor (PDGF) is a central mediator of mesangioproliferative glomerulonephritis (GN). In experimental mesangioproliferative GN, PDGF-DD serum levels, unlike PDGF-BB, increased up to 1000-fold. Methods. We assessed disease activity in 72 patients with GN, established a novel PDGF-D ELISA and then determined their PDGF-DD levels. In parallel, we studied renal PDGF-DD mRNA expression by RT-PCR. Results. PDGF-DD serum levels in patients with IgA nephropathy (IgAN) were significantly higher (1.67 ± 0.45 ng/ml) and in patients with lupus nephritis significantly lower (0.66 ± 0.86 ng/ml) compared to healthy controls (1.17 ± 0.46 ng/ml), while patients with focal segmental glomerulosclerosis, membranous GN and ANCA-positive vasculitis did not differ from controls. The subgroup of IgAN patients with elevated PDGF-DD levels (27% of samples) did not differ in their clinical features from those with normal PDGF-DD levels. In IgAN patients with repetitive PDGF-DD determinations, most exhibited only minor fluctuations of serum levels over time. Intrarenal PDGF-DD mRNA expression did not differ between controls and patients, suggesting an extrarenal source of the elevated PDGF-DD in IgAN. Conclusions. Serum PDGF-DD levels were specifically elevated in patients with IgAN, in particular in those with early disease, i.e. preserved renal function. Our data support the rationale for anti-PDGF-DD therapy in mesangioproliferative G

    Spontaneous Symmetry Breaking in Twisted Noncommutative Quantum Theories

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    We analyse aspects of symmetry breaking for Moyal spacetimes within a quantisation scheme which preserves the twisted Poincar\'e symmetry. Towards this purpose, we develop the LSZ approach for Moyal spacetimes. The latter gives a formula for scattering amplitudes on these spacetimes which can be obtained from the corresponding ones on the commutative spacetime. This formula applies in the presence of spontaneous breakdown of symmetries as well.We also derive Goldstone's theorem on Moyal spacetime. The formalism developed here can be directly applied to the twisted standard model.Comment: +13 pages; minor changes in references,To appear in Phys Rev

    Emission patterns of neutral pions in 40 A MeV Ta+Au reactions

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    Differential cross sections of neutral pions emitted in 181Ta + 197Au collisions at a beam energy of 39.5A MeV have been measured with the photon spectrometer TAPS. The kinetic energy and transverse momentum spectra of neutral pions cannot be properly described in the framework of the thermal model, nor when the reabsorption of pions is accounted for in a phenomenological model. However, high energy and high momentum tails of the pion spectra can be well fitted through thermal distributions with unexpectedly soft temperature parameters below 10 MeV.Comment: 16 pages (double-spaced), 5 figures; corrections after referee's comments and suggestion

    Thermal Bremsstrahlung photons probing the nuclear caloric curve

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    Hard-photon (Eγ>_{\gamma}> 30 MeV) emission from second-chance nucleon-nucleon Bremsstrahlung collisions in intermediate energy heavy-ion reactions is studied employing a realistic thermal model. Photon spectra and yields measured in several nucleus-nucleus reactions are consistent with an emission from hot nuclear systems with temperatures TT\approx 4 - 7 MeV. The corresponding caloric curve in the region of excitation energies ϵ\epsilon^\star\approx 3{\it A} - 8{\it A} MeV shows lower values of TT than those expected for a Fermi fluid.Comment: 13 pages, 3 figures. To appear in Physics Letters

    Software and hardware platform for testing of Automatic Generation Control algorithms

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    Development and implementation of new Automatic Generation Control (AGC) algorithms requires testing them on a model that adequately simulates primary energetic, information and control processes. In this article an implementation of a test platform based on HRTSim (Hybrid Real Time Simulator) and SCADA CK-2007 (which is widely used by the System Operator of Russia) is proposed. Testing of AGC algorithms on the test platform based on the same SCADA system that is used in operation allows to exclude errors associated with the transfer of AGC algorithms and settings from the test platform to a real power system. A power system including relay protection, automatic control systems and emergency control automatics can be accurately simulated on HRTSim. Besides the information commonly used by conventional AGC systems HRTSim is able to provide a resemblance of Phasor Measurement Unit (PMU) measurements (information about rotor angles, magnitudes and phase angles of currents and voltages etc.). The additional information significantly expands the number of possible AGC algorithms so the test platform is useful in modern AGC system developing. The obtained test results confirm that the proposed system is applicable for the tasks mentioned above

    Робочий зошит до конспекту лекцій з дисциплін “Основи побудови мікропроцесорних систем керування”, “Мікропроцесорна техніка”, “Програмні засоби систем керування” для студентів спеціальностей АГ – 8.092501 Автоматизоване управління технологічними процесами; АТ,ME – 8.091401 Системи управління й автоматики; СМ – 8.091501 Комп`ютерні системи та мережі

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    Дані методичні вказівки призначуються для вивчення апаратних та програмних засобів мікропроцесорних систем управління (МПС). У процесі вивчення дисципліни "Мікропроцесорні системи" студенти вивчають структуру, архітектуру, сигнали та системи команд однокристального мікроконтролера К1816 ВЕ51. Розглянуті питання організації паралельного та послідовного вводу- виводу, оганізація мікропроцесорних контролерів МПК). Схемні рішення, які приведені у методичних вказівках можуть бути використані при виконанні курсових і дипломних проектів студентами спеціальностей "Комп’ютеризовані системи управління і автоматики" (АТ) і "Автоматизація технологічних процесів гірничих підприємств" (АГ) та "Комп’ютерні системи та мережі" (СМ)
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